Triangles and angles

[Andrew Plewe]

A015616? The description reads " Number of triples (i,j,k) with 1 <= i<j<k
<= n and GCD{i,j,k} = 1." Below are a.) the intermediate terms (which
appears to be the same as A000741), and b.) the running total, which is the
same as A015616, based on my hand calculations.

3 = 1 (1)
4 = 3 (4)
5 = 6 (10)
6 = 9 (19)
7 = 15 (34)
8 = 18 (52)

	-Andrew Plewe-


-----Original Message-----
From: franktaw at netscape.net [mailto:franktaw at netscape.net]
Sent: Monday, September 25, 2006 2:29 PM
To: seqfan at ext.jussieu.fr
Subject: Triangles and angles

Consider all triangles with integral sides, no side longer than n.

How many different triangles are there, up to similarity?  I.e., how
many triples a,b,c with a<=b<=c<a+b, c <= n, and gcd(a,b,c) = 1?

How many different angles do those triangles have?

Franklin T. Adams-Watters

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